Cutting bits are used in various road milling, mining and excavating operations. The bits are mounted on a support structure such as a rotary drum. Each bit typically has a hard wear resistant tip made of a material such as tungsten carbide attached to a generally conical steel head of the bit. A problem with such designs is that the softer steel backing material erodes during cutting operations.
Wear resistant cutting bits have been developed in order to increase erosion resistance. For example, U.S. Pat. No. 4,725,098 to Beach discloses the deposition of a hard facing material on the steel nose of a tool body. U.S. Pat. No. 5,417,475 to Graham et al. discloses the installation of a ring of hard material on the front surface of a steel nose surrounding the hard cutting tip of a cutting tool. U.S. Pat. No. 6,709,065 to Peay et al. discloses the use of an annular ledge of hard material mounted near the steel nose of a cutting tool. Published U.S. Application No. 2005/0035649 to Mercier et al. discloses the installation of hard wear rings on a stepped shoulder of a cutting bit body. Despite these known designs, a need still exists for cutting bits which exhibit improved wear resistance.